JUDGMENT :

HIMA KOHLI, J.

1. The appellant No.1, a public listed company, that provides Scheduled Air Transport Services in the name and style of “IndiGo” (hereinafter referred to as ‘IndiGo’) is aggrieved by the judgment dated 20.12.2017 passed by the learned Single Judge, dismissing the writ petition filed by it (W.P.(C) 9820/2017) praying inter alia for issuance of a writ of certiorari and prohibition in respect of the directions contained in the letters dated 06.09.2017, 28.09.2017, 05.10.2017 and 21.10.2017 issued by the respondent No.2/Delhi International Airport Limited (in short ‘DIAL’), directing it to operate its flights to and fro Mumbai, Kolkata and Bengaluru w.e.f. 04.01.2018 from Terminal-2 (in short ‘T-2’) of Indira Gandhi International Airport (in short ‘IGI Airport’). Additionally, the appellants/petitioners had prayed for issuance of a writ of certiorari in respect of a letter dated 14.06.2017 issued by the respondent No.1/Ministry of Civil Aviation, Union of India, permitting the respondent No.2/DIAL to decide a suitable course of action for shifting of the operations of the appellants/IndiGo, respondent No.5/Spice Jet Limited (in short ‘SpiceJet’) and respondent No.6/Go Air (India) Limited (in short ‘GoAir’) to ensure that Terminal-1 (in short ‘T-1’) is decongested and T-2 is meaningfully utilized.

2. Before considering the arguments advanced by learned counsels for the parties, we may refer to the sequence of dates and events that culminated in the directions issued by the respondent No.2/DIAL, calling upon the appellants and the respondents No.5 and 6 to operate their flights in respect of three sectors, i.e., Mumbai, Kolkata and Bengaluru w.e.f. 04.01.2018, from T-2.

3. Taking note of the exponential growth witnessed by the Indian aviation sector, particularly in the domestic sector and a steep rise in the operation of low costs carriers, the respondent No.1/UOI held a meeting on 05.10.2015, directing the respondent No.2/DIAL and respondent No.3/Airport Authority of India (in short 'AAI') to take immediate steps to increase the number of boarding gates, widen airport entry gates, increase post security check-in areas and boost the CISF manpower deployment. As a result, the respondent No.2/DIAL took a decision to implement the approved Master Plan, 2016 for development and expansion of T-1 so that its existing capacity of 20 million passenger per annum (in short ‘mppa’) is enhanced to 35-40 mppa, and to renovate/modernize the existing T-2, that is primarily used for Haj operations. Once the renovation work at T-2 was completed, several meeting were held by the respondent No.2/DIAL with the domestic airline operators in order to operationalize T-2 so as to ease the congestion at T-1. After some deliberations, the respondents No.1/UOI and respondent No.3/AAI decided on 07.06.2017 that all airlines operating from T-1 should discuss amongst themselves, the modalities of operationalizing T-2 and suggest the course of action to the respondent No.2/DIAL within one month. In furtherance to the said decision, the respondent No.2/DIAL made efforts to amicably resolve the issue so that an interim arrangement could be made to shift flight operations of the three airlines, i.e., IndiGo, SpiceJet and GoAir so that the entire redevelopment work could be executed in approximately 42 months.

4. Respondent No.2/DIAL addressed a communication dated 16.08.2017 to all the three airlines, calling upon them to take a decision of their own as to which of their operations did they propose to shift from T-1 to T-2. The respondent No.2/DIAL took a stand before the learned Single Judge that only when the three airlines had failed to intimate their decision, was DIAL compelled to issue a communication dated 06.09.2017, stating inter alia that w.e.f. 29.10.2017, all fight operations of the three airlines, to and fro the three sectors, refer